Find and implement parler_tts alternative

[stefanfrench]

Currently, there is an issues installing parler_tts inside codespaces. It uses a dependency that also tries to install from git and fails. In the short-term, we've forked parler_tts to trim dependencies.
Long-term, we'd like to find an alternative to parer_tts without these dependency issues in codespaces.

Acceptance criteria

• Alternative to parler_tts installs in codespaces without issues
• Alternative to parler_tts gives comparable results in terms of speech quality
• • Alternative to parler_tts works in similar speed
• Alternative can be implemented and works as part of end-to-end Blueprint

UAT
As a user, when I upload my document, I can generate a natural sounding audio podcast.

[Kostis-S-Z]

Promising options:

• https://github.com/NexaAI/nexa-sdk
• https://huggingface.co/microsoft/speecht5_tts
• https://huggingface.co/facebook/mms-tts-eng
• https://huggingface.co/suno/bark-small
• https://github.com/PABannier/bark.cpp
• https://github.com/rhasspy/piper